Portable electric power apparatus

ABSTRACT

Two portable battery packs are removably mounted on a truck and connected to the truck&#39;&#39;s electrical system. Each pack contains four 6-volt battery units which are wired to a battery pack connector mounted at the rear of the battery pack housing. Means are provided for connecting the battery units in parallel for charging by the truck generator alternator or battery. When the pack is (1) withdrawn from the truck, and (2) used to power a tool, the battery units are connected in suitable series parallel - to provide output voltages greater than the charging voltage. In one embodiment, a charging rack is permanently mounted on and to the truck, the rack having a mating connector which during the charging process engages the battery pack connector. A program connector at other times engages the battery pack connector to provide proper output voltage at the battery pack output connector. In another embodiment, the charging rack is dispensed with and two double pole double throw switches are used to effect the different series or parallel connections in and to the battery pack.

Jones 1 PORTABLE ELECTRIC POWER.

APPARATUS [72] Inventor: Jack ,ione l ima, Ohio [73] Assignee: NationalCan Reti'nning Company,

Lima, Ohio [22] Filed: Dec. 28, 1971 [21] Appl. No.: 212,918

[52] US. Cl. ..307/150, 307/9, 307/71, 136/173, 320/2, 320/7, 320/16[51]. Int. Cl...... ..H02j 7/00 [58] Field of Search ..307/9,10 R, 10BP, 71, 149, 307/150; 136/173; 320/2, 6, 7, 16

[56] References Cited UNITED STATES PATENTS I 1,425,689 8/1922 Powell..320/2 1,605,345 11/1926 Hawkins ....l ..320/2 2,005,623 6/1935 Meyer..320/2 2,173,736 9/1939 Thomas ..320/2 2,375,866 5/1945 Nelms et al..'..320/2 2,483,673 10/1949 Robinson et a1. ..320/2 X 2,808,521 10/1957Scal ..307/150 2,978,596 4/1961 Robirds ..320/2 X 3,056,893 10/1962 Russ..307/150 3,510,745 5/1970 Futterer ..320/7 [451 Sept. 26, 1972 PrimaryExaminer-William M. Shoop, Jr. Attorney-Jerome R. Cox

[5 7] ABSTRACT for charging by the truck generator alternator or bat-'tery. When the pack is (1) withdrawn from the truck,

and (2) used to power a tool, the battery units are connected insuitable series parallel to provide output voltages greater than thecharging voltage.

In one embodiment, a charging rack is permanently mounted on and to thetruck, the rack having a mating connector which during the chargingprocess engages the battery pack connector. A program connector at Iother times engages the battery pack connector to provide proper outputvoltage at the battery pack output connector.

'1n another embodiment, the charging .rack is dispensed with and twodouble pole double throw switches are usedto effect the different seriesor parallel connections in and to the battery pack.

18 Claims, 14 Drawing Figures mcmcnsm m2 v sum 2 or 4 INVENTOR JACK D.JONES "FIG. 5

ATTORNEY P'ATENTEDSms I972 ,58c E kEl 53b F IG.9

SHEET 3 OF 4 FIG. IO

U. i fi INVEINTOR' JACK o. JONES ATTORNEY I I PORTABLE ELECTRICAPPARATUS BACKGROUND OF THE INVENTION The invention relates to equipmentfor supplying electrical power to por able. equipment. This inventionrelates more particularly to a battery pack and its. as-

sociated charging apparatus which is carried on a service vehicle andconveniently maintains continuous supply of electrical power.

Many construction. and repair service men utilize power tools toefficiently perform their services. These power tools are used atremotelocations such as construction sites and power and telephonedistribution mers, andlights. Such serv'ice-men working inthe field needthis continuous supply of power so that they will not be required tointerrupt their work to wait for a batteryto charge;

There is, therefore, a need for a portable electric power apparatuswhich will continuously recharge its battery packswhen they are notbeing used and, which can do so without requiring the worker to leavethe area in which he is working in order to return the battery packs toa central charging location and without requiringthe worker to engage ina substantial amount of electrical connection and switching in order tocharge the batteries properly. The power tools normally available oftenoperate from a 24-volt d-c source. Some, however, operate from a l2-voltsource and others from a 6-volt source. A motor vehicle electricalsystem ordinarily provides a l2-volt system. There is a need therefore,for a portable electrical power apparatus which can be charged by a12-.volt vehicle electrical system and yet, which provide the workerwith a selection of 24 l2 or 6 volts as the output for his power tools."It is further desirable that theworker be able to select the desiredoutput voltage simply and without extensive wiring or switching.

SUMMARY or THE INVENTION r'earwardly facing battery pack connector whichis electrically connected to the battery units. The battery pack'alsohas a power outlet for connection to a tool. The battery pack ismountable in a charger rack which is permanently mounted. on a motorvehicle. The charger rack has a substantially vertically oriented rearpanel and one or more support tracks extending substantiallyhorizontally from the rear panel for slidably receiving battery packs. Aforwardly facing charging connector is mounted to the rear panel and ispositioned to slidingly engage the battery pack connector as the batterypack is slid along the first supp rt track toward the rear panel. Thischarging connector is electrically connected to the battery chargingcircuitry, a

portion of which is mounted in the charger rack.

The battery pack electrical connector has a pair of contacts for eachbattery unit. Each pole of each battery unit is connected to a differentone of these contacts. The charging connector, which ismatinglyengageable at times with the battery pack connector has itselectrical terminals conductively connected to a source of input, d-ccharging power. When the charg ing connector is engaged with the batterypack connector, the positive poles of the battery units are connected tothe positive poles of said source of charging power and thenegativepoles of the battery units are connected to the negative poles of saidsource. A program connectoris alternatively matingly engageable at timesto the battery pack connector and has its terminals interconnected forsuitable interconnecting the poles of the battery units to permitselection of the output voltage and consumption of power by the powertool when the program connector is engaged in the battery packconnector.

It is therefore an object of the invention to provide an improvedportable electric power apparatus.

Another object of the invention is to provide a portable electric powerapparatus which makes a substantially continuous supply of poweravailable to a worker in the field.

Another object of the invention is to provide a portable battery packand associated charging rack which enable the-work to sumultaneouslystore and charge the battery packs with maximum simplicity and the leastthought and effort.

Further objects and features of the invention will be apparent from thefollowing specification and claims when considered in connection withthe accompanying drawings illustrating the embodiments of the invention.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a view in front elevation of acharger rack embodying the invention.

FIG. 2 is a view in side elevation of the charger rack of FIG. 1 with aportable battery pack partially slid into the lower storage position onthe charger rack.

FIG. 2A is a view in front elevation of the battery pack illustrated inFIG. 2.

FIG. 2B is a view in rear elevation of the battery pack illustrated inFIG. 2.

FIG. 3 is a plan view of the embodiment FIG. 1.

FIG. 4 is a view in front elevation of an alternative embodiment of theinvention.

FIG. 5 is a view in perspective of the charging rack illustrated in FIG.1.

FIG. 6 is a schematic diagram of a battery pack embodying the invention;

FIG. 7 is a schematic diagram of the charging cirillustrated in cuitrywhich is incorporated in the charger rack illusa source of input d-ccharging power supplies electrical current for recharging the batterypack; and

example, the terms connected" or conductively connected are notrestricted to direct electrical connection. Such connections may be madethrough additional electrical elements where such connection isfunctionally equivalent.

DETAILED DESCRIPTION FIGS. 1 through 3 and FIG. 5 illustrate a portablebatterypack and its associated charging rack 12. v The battery pack 10has a box-like housing 14 with a carrying handle 15 attached to its topface. I I

v The battery pack contains several battery unitsand its internalcontents are described below. A recessed, rearwardly facing battery packconnector 18, visible in FIG. 2B, is mounted to a rear wall 19 of thehousing 14. The battery pack connector 18 is a female connector havingeight terminal contacts. A-Tee receptacle 20 is mounted to the frontside 21 of the battery pack 10 for receiving a male plug from the powercord of any tool it may be desired to supply with power.

The charger rack 12 is normally, though not necessarily, permanentlymounted to a motor vehicle which is not shown. The charger rack 12 has asuitable support frame 22 to which a substantially vertically orientedrear panel 24 is attached. A first battery pack support cradle isconstructed on the lower portion of the charger rack 12 to slidablyreceive the battery pack 10 and retain it in a stored position. Thesupport cradle 30 is a track extending substantially horizontallyforward from the rear panel 24. The track comprises four parallel rightangle, structural beams 32, 34, 36, and 38 for slidably and closelyreceiving in their acute angles four parallelside edges of the batterypack housing 14. These four. structural beams retain the battery packhousing against vertical and lateral movement.

A forwardly facing, charging connector 40 is mounted to the rear panel24 centrally of the lower battery pack cradle 30. The charging connector40 is a male connector positioned to slidingly engage the battery packconnector 18 as the battery pack 10 is slid into the first cradle 30toward the rear panel 24. The charging connector 40 is connected to thebattery charging circuitry, described below, which is mounted in thecharger rack 12. A second battery pack cradle 42 is constructed at theupper portion of the charger rack 12. The upper battery pack cradle 42is substantially identical to the lower cradle and has four parallelstructural beams 44, 46, 48 and 51 for receiving a second battery packwhich is not illustrated but which is identical to the battery pack 10.The upper battery pack cradle 42 is also provided with a chargingconnector 50 which is mounted to the rear panel 24 and is substantiallysimilar to the lower charging connector 40. Intermediate, the lowerbattery pack cradle 30 and the upper battery pack cradle 42 is thecharging circuitry of the charging rack which lies behind a controlpanel 52. The control panel 52 has a pair of ammeters 54 and 56 formonitoring the charging current to the battery packs in the upper andlower battery pack cradles 42 and 30.

Male program connectors 58 (which numeral is used to designatecollectively connectors 58a, 58b and 580) and 60, (which numeral is alsoused collectively to designate connectors identical with 58a, 58b and58c) are all described in detail below and are received in mating femalecontrol panel connectors which are mounted on the control panel 52. Aswitch 62 is provided to turn the charging circuitry on and off. A mainpilot lamp 64 is illuminated when the charging circuitry is turned on. Afirst charging pilot light 66 is illuminated when the program connector60 is properly inserted in its control panel connector. A similar secondpilot light 68 is illuminated when the other program connector 58 isproperly inserted in its control panel connector. The male programconnectors 58 and 60 have prongs which are identical with the prongs ofthe charging connectors 40 and 50, so that they may, as described below,at times, be matingly engaged in the battery pack connector, such as thebattery pack connector 18 illustrated in FIG. 2B.

The electrical circuitry of the battery pack 10 is illustrated in FIG.6. The battery pack 10 has four, preferably 6-volt, battery units 70,72, 74 and 76. Each battery unit preferably, is a 6-volt, multi-cellbattery, such as is commercially available. However, the battery unitsmay be suitable groupings of cells tied together to functionequivalently as a single battery unit. The battery pack connector 18 hasa pair of contacts for each battery unit so that the preferred connectorhas eight contacts. Each pole of each battery unit is connected to adifferent one of the contacts. For simplicity, the positive poles inFIG. 6 are connected to the four right hand contacts. The negative polesare connected to the four left hand contacts. Thus, each connectorcontact of the battery pack connector 18 represents a connection to asingle pole of a single battery unit. In addition, the contact 78, whichis connected to the positive pole of the battery unit 76, is alsoconnected to the Tee receptacle 20. The contact is connected to theother contact of the Tee receptacle 20 and as well as to the negativepole of the battery unit 74. Thus, the output power terminals, which areavailable for connection through receptacle 20 to a power consumingtool, are conductively connected to a positive pole of one of thebattery units and to the negative pole of another battery unit. However,without any connections between the terminal contacts of the batterypack connector 18, no current could flow into a tool connected to theTee receptacle 20. The program connectors provide the neededconnections.

FIGS. 8, 9, and 10 indicate alternative program connectors which arematingly engageable at times to the battery pack connector 18. Theterminals of the program connectors are conductively interconnected forsuitably interconnecting the poles of the battery units for selectingthe output voltage at the receptacle 20 and to permit consumption ofpower by a power tool when the program connector is engaged in thebattery pack connector 18.

Tee receptacle 2!).

' Finally, if-the program connector 58c illustrated inv v Thus, forexample, if. the program connector 58a'of FIG. 8 is matingly engaged inthe battery pack connector 18, then the battery units 74, 70, 72, and 76are series connected to the terminals of the Tee receptacle 20. Theprogram connector of FIG. 8 would connect the positive pole of thebattery 74 to the negative pole of the battery 70. Similarly, it wouldalso connect the positive pole of the battery 70 to the negative pole ofthe battery 72 and the positive pole of the battery 72 to the negativepole of the battery 76. The positive pole of the battery 76 and the.negative pole of the battery 74 'arefperman'ently connected to therespective contacts of the Tee receptacle 20. With four 6-volt batteryunits, the use of the program connector of FIG. 8 thus provides a24-volt power supply at the Tee receptacle 20.

' If the program connector 58b illustrated in FIG. is matingly engagedin the battery pack connector 18, then the four battery units 70, 72, 74and 76 are parallel connected to provide a 6-volt power supply at theFIG. 9 is matingly engaged in the battery pack connector 18, then thebattery units ,72 and 74 are parallel connected to each, other,'thebattery units 70 and 76 are parallel connected to each other and theparallel connected pairs are series connected to each other to providean output voltage of 12 volts at the Tee receptacle 20. Looking at itfrom another viewpoint, 70 and 74 are series connected, and 72 and 76are series connected, and the two series are arranged in parallel. Thisprovides a l2-volt supply at Tee receptacle 20.

Thus, a person using the portable battery pack 10 merely withdraws thebattery pack from the charger rack 12 illustrated in FIGS. 1-3 andinserts the appropriate program connector in the battery pack connectorat the rear of the battery pack. In doing so, he selects the desiredoutput voltage.

FIG. 7'illustrates the charging circuitry which is used to charge thebattery pack 10and the similar battery pack whichis mountable in thecradle 42 at the upper portion of the charger rack 12. A workman, whenreplacing a portable battery pack in. the charger rack, must firstremove the program connector 58a, 58b, or 580 from the rear of thebattery pack so that the battery pack connector can matingly engage withthe charging connector when the battery is slid into its cradle on thecharger rack. To assure that the workman removes the program connectorand to assure that the program connector is not mislaid, I haveprovided-a control panel connector 61 which is connected to the uppercradle and a control panel connector 63 which is connected to the lowercradle to receive the program connectors when they are not mounted tothe battery packs. Additionally, circuitry is provided to prevent thecharging of the battery and the illumination of the appropriate pilotlights until the workman has properly positioned the program connectorin the appropriate control panel connector. Thus, after the battery pack10 is slid in the lower cradle 30 into engagement with the chargingconnector 40, the program connector 58 (either 58a or 580) must beinserted in the control panel connector 63 before the lower battery packwill'begin charging from charging connector 40.. Similarly, a programconnector must be inserted in the control panel connector 61 before theupper battery pack can begin receiving charge from the chargingconnector 50. To simplify explanation of the charging circuitry, Iassume that the operator has inserted the program connectors properly inthe control panel connectors and the connection made by these connectorsis therefore illustrated in phantom or in dotted lines on the controlpanel connectors 61 and 63.

The vehicle generator or alternator is connected to power inputterminals 101, the negative terminal of which is connected to a groundterminal 103 on a terminal board 105. The main on-ofi switch 62,accessible at the control panel 52, is a double-pole, single throwswitch which, when turned on, connects the positive terminal from theinput power terminal 101 to the inputterminal 107 of the terminal board105. The terminals 103 and 107 on the terminal board 105 are alsoconnected to the input of a current limiting charger module the functionof which is to reduce the charging current as the batteries are suitablycharged. However, such a module'is known in the art and is not-necessaryto the invention, and therefore the internal circuitry is notillustrated. However, in an equivalent manner,

' although sacrificing the power saving feature afforded by the currentlimiting module, the terminals 103 and 107 can both be directlyconnected to the terminals 109 and lllre spectively. As illustrated,however, terminals 109 and lll are the output terminals of the currentlimiting charger module.

The right hand terminal contacts of the charging connectors 40 and 50are interconnected together and connected to the ground output terminal109. This effectively connects the negative ground pole of the source ofinput d-c charging power to the, negative poles of all of the batteryunits in the battery packs whenever the charging connectors areconductively engaged in the battery pack connectors. It must be notedthat FIG. '6 is looking at the circuit from the opposite direction toFIG. 7 so that the left hand contacts of FIG. 6 engage with the righthand contacts of FIG. 7. The positive output terminal 111 is thepositive pole of the source of d-c input charging power and .isconnected through a series connected diode 113 and the ammeter 54 andthrough the program plug 58 (58a or 580) inserted in the panel connector61 to the left hand contacts of the uppercharging connector 50. Thediode l 13 is connected in a polarity to permit charging current to flowbut to prevent discharge of the battery, especially in a situation wherean alternator is used. The diode is provided with a suitable heat sink.This effectively connects the positive pole of the source of input, d-c,charging power to the positive poles of all the battery units which arein the battery pack stored in the upper cradle 42. Similarly, thepositive output terminal 111 is connected through a similar diode 115into the ammeter 56 and the program connector 58 (58a or 58c) insertedin the control panel connector 63 to the left hand terminals of thelower charging connector 40. v

This effectively connects the positive pole of the source of input, d-c,charging power to the positive poles of all the battery units in thebattery pack which is stored in the lower cradle 30 of the charging rack12.

The lower contacts 132 of the switch 62 connect the negative pole of theinput charging supply at the terminal 109 to one side of the main pilotlamp 64. The opposite side of the main pilot lamp 64 is connected to 7the positive pole of the source of input power at terminals 101 by theupper contacts 130 of the switch 62. Thus, whenever the switch 62 isclosed, the main pilot lamp 64 is illuminated. Additionally, thecontacts 130 of the switch 62 also connect the positive pole of theinput source at the terminals 101 to one side of each of the chargingpilot lamps 66 and 68. The opposite side of the charging pilot lamp 66is connected through the control panel connector 61 and the engagedprogram plug 58 and through the closed contacts 132 to the negativeground terminal 109. Therefore, if the main switch 62 is closed, and ifa program plug is inserted in the connector 61, the charging pilot light66 will be illuminated. Similarly, the opposite side of charging pilotlight 68 is connnected through the control panel connector 63 andthrough an engaged program plug and through the closedcontacts 132 ofthe switch .62 to the ground terminal 109. The charging pilot lamp 68 issimilarly illuminated whenever the switch 62 is closed and a programplug is engaged in the control panel connector 63. 4

FIG. 4 illustratesan alternative embodiment of the invention comprisinga rack 212 for receiving and charging a single battery pack 210. Thebattery pack 210 has a hand carrying strap 213 mounted on its forwardlydirected face. The charger rack 212 has a control panel 252 with anammeter 254 and a main switch 264. The charger rack 212 has a box-likeopening 230 for slidably receiving the battery pack 210. A mounting yoke275 is bolted at its opposite ends by bolts 276 and 277 to the chargingrack 212.

The internal circuitry of the embodiment of FIG. 4 utilizes half thecircuitry illustrated in FIG. 7. In addition, in the embodimentillustrated in FIG. 4, the charger module whose terminals are indicatedat the terminal board 105 illustrated in FIG. 7 andthe pilot lights havebeen eliminated from the circuitry.

In order to avoid excessive drain on the vehicle battery due to verysubstantially discharged battery packs, an automatically controlledsingle pole double throw switch may be employed. Such a switch can becontrolled by an electrical timer to alternately apply the alternator orgenerator output to the vehicle battery and to the charging rack. Forexample, the entire alternator output can be applied to charge theportable battery packs for minutes. Then the timer would switch to applythe alternator output to the vehicle battery. In this way, vehicleoperation is unaffected but the charger rack circuitry is neverconnected parallel to the vehicle battery.

In FIG. 11 is shown a perspective view showing respectively a chargingbox 290 having on its face a plug 58 which is for convenience insertedin a dummy socket, a pair of T receptacles a and 20b, and an ammeter291. Connected to the box 290 is a power input electrical cable 292 andalso a battery charging electrical cable 294. A switch 293 (see FIG. 12)is provided having a handle 296 shown on the front of box 290.Associated with the box 290 are a pair of batteries designatedrespectively 297 and 298. In the rear of the battery 298 is an outletplug or T receptacle 20 for connection to or for receiving a male plugfrom a power cord of any tool it may be desired to supply with power. Inthe front .of battery'297 there is shown a male plug battery packconnector 299 which is adapted to fit into minals 304 and 305 of Treceptacles 20a and 20b respectively. It is also connected through abranch lead 306 to a charger regulator 307 as at 308. The positiveconventional current supplied at 308 may at times pass through a lead309 to a 10 ampere ammeter 291 to show the charging rate. After passingthrough ammeter 291, current may flow at times through lead 312 toswitch contacts 313 and 314. These contacts are part of a double throwgang switch 293 having movable blades 316, 317, 318 and 319. When theblades are in the position shown, no current can flow through 306, 309or 312. However, if the switch 293 is moved downward, the. blades 316,317, 318 and 319 are also moved downward to make contacts withappropriate switch contacts. Thus, blades 316 and 317 make contacts withcontacts 314 and 313 respectively. Thereupon, positive conventionalcurrent flows from 303 through leads 306, 309, 312 and (utilizing switchblade 316) 321 to positive terminals 322 and 323 of male plug 299heretofore designated pack connector 299. Current also flows from 303through leads 306, 309, 312 and (utilizing switch blade 317) 325 topositive terminals 326 and 327 of male plug 299. Referring to thebattery 297 indicated in the lower central part of FIG. 12, it may benoted that the contacts 331-334 inclusive and 322, 323, 326 and 327 areduplicates of the same contacts shown in the male plug 299 to the left.This duplication is made so that hopefully the electrical connection ofthe contacts to the respective battery units 370, 372, 374, and 376,when the male plug 299 is inserted in the female socket 18, may be moreeasily shown. The male plug 299 is duplicated in the two parts of theFigure for the same reason. Assuming the male plug 299 is inserted inthe female receptacle 18 of the battery pack 297, current passes throughthe battery pack in parallel through the four 6-volt battery units 370,372, 374 and 376 of battery 297 and then back to the plug 299 and thenegative contacts 331, 332, 333 and 334. Contacts 331 and 332 areconnected through lead 335, switch blade 318, contact 336, leads 337,338 and 339 to negative battery terminal 302. Contacts 333 and 334 areconnected through lead 355, switch blade 319, contact 357, leads 337,338 and 339 to negative battery terminal 302. Thus, the battery pack 297is recharged from vehicle battery 300 or from the alternator orgenerator of the vehicle, one of which is effectively connected to theterminals of the battery 300.

' Now, assuming it is desired to supply 24-volt power to receptacles 20aand 20b, the switch 293 is moved to its upper position thus causingswitch blades 316, 317, 318 and 319 to make contacts with switchcontacts 341, 342, 343 and 344 respectively. Thereupon, positiveconventional current may flow from battery pack 297 through positiveterminals 322, 323, 326 and 327 as follows. Again, for example, fromunits 370 and 372 through positive contacts 326 and 327, lead 325,

9 I switch blade 317, contact 342, lead 346, contact 343, switch blade318, lead 335, negative contacts 331 and 332 of male plug 299 to batteryunits 374 and 376 of batteryvpack 297, and then to positive contacts 322and 323, lead 321, switch blade 316, contact 341 and lead 339 tonegative terminal 302 of battery 300. The two battery units 370 and 372acting in parallel are placed in series with battery units 374 and 376,thus supplying l2-volt power to battery 300. The l2-volt power frombattery pack 297 passing through the battery 300 is placed in serieswith the l2-volt voltage of battery 300 thus supplying 24-volt voltageto slots 304 and 305 of T receptacles 20a and 20b. Negative slots 351and 352 of T receptacles 20a and 20b are connected through lead 353,switch contact 344, switch blade 319, lead 355,

negative contacts 333 and 334 of male plug 299 and to negative terminalsof battery units 370 and 372 thus completing the series circuit throughvehicle battery 300 and battery pack 297. l

The integrated circuit charger I regulator 307 prevents a greatervoltage than 7.2 volts from flowing from 12-volt'battery 300 (or thealternator or generator) to battery pack 297 inrecharging it. Thecharger regulator 307. is connected through lead 356, switch contact357, leads 337, 338 and 339 back to car battery negative terminal 302.

In operation, 'thebattery packs are normally stored in the charging rack12 with the battery pack connectors, such as the connector 40. With themain switch 62 closed, charging current can flow to charge the batteryunits in the respective battery packs. Whenever the service vehicleengine is running, the'batteries are being suitably charged. Forexample, as a service man drives from one location to another, hisportable battery packs are being simultaneously recharged so thatwhenever he arrives at the job, the battery packs are ready foroperation.

When the service man arrives at his job site, he simply grasps one ofthe battery packs by the handle, slides it toward him and removes itfrom the charging rack. He then reaches on the control panel and removesthe program'plug from the controlpanel and inserts it at the rear of thebattery pack in the battery pack connector. He may have available to himprogram plugs of the types illustrated in FIG. 8 (58a), FIG. 9 (58c) andFIG. 10 (58b). The plug of the power tool is inserted in the appropriatereceptacle in the battery pack such as the receptacle and the tool isnow ready for use. The tool and the battery pack may be easily handcarried to the site of the work to be preformed.

If a job is completed, the reverse sequence of events occurs. The toolis unplugged from the battery pack, the program plug is removed from therear of the battery pack and inserted in the control panel connector onthe charging rack. The battery pack is then slid along the tracks of itscradle into its stored charging position on'the charging rack. As theserviceman drives away, the battery pack is appropriately charged.

In the alternative, if the serviceman drains substantial power from thebattery pack while working on the job, he may return the drained batterypack to the charging rack as described above. He then can irh-"mediatelyremove the second battery pack from the charging rack withsimilar steps to immediately have available an alternative supply ofelectrical power. The serviceman continues to use the tools withoutinterruption and at the same time, whether the service vehicles motor isrunning or not, the first battery will be suitably recharged. This canoccur because the previously mentioned, but not shown, current limitingcharger module also limits the maximum charging voltage to 7.2 voltswhile receiving an input voltage sufficiently high for its properoperation from the l2-volt vehicle battery even when the engine is notrunning. Thus, by alternately using the two battery packs, a continuoussupply of electrical power is always available.

It is to be understood that while the detailed drawings and specificexamples given describe preferred embodiments of the invention, they arefor the purpose of illustration only, that the apparatus of theinvention is not limited to the precise details and conditionsdisclosed, and that various changes may be made therein withoutdeparting from the spirit of the invention which is defined by thefollowing claims.

I claim:

1. An electric power apparatus comprising:

a. a portable battery pack comprising:'

1. a plurality of battery units mounted in said pack,

each battery unit having a positive and a negative pole;

2. a battery pack electrical connector having a pair of contacts foreach battery unit and having each pole of each battery unit connected toa different one of said contacts;

3. a pair of output power terminals for connection to a power consumingtool; and v 4. means for conductively connecting one output terminal toa positive pole of one battery unit and the other output terminal to thenegative pole of another battery unit; and

b. a cooperating battery charging apparatus compris l. a source of inputd-c charging power having a positive pole and a negative pole;

2. means for at times conductively connecting the positive poles of saidbattery units to the positive pole of said source and for conductivelyconnecting the negative poles of said battery units to the negative poleof said source;

whereby when said source is so connected the battery units are connectedto said source in parallel and the batteries are charged in parallel;and

0. means for at times conductively interconnecting the poles of saidbattery units to select the output voltage to said output powerterminals to provide for selected consumption of power by said powertool.

2. An apparatus according to claim 1,

wherein the means for at times conductively interconnecting the poles ofthe battery units at times interconnect the poles of at least two of thebattery units in series to at least double the output voltage of saidbattery pack above the output voltage of any individual battery unit;

whereby the portable electric power apparatus is charged in a parallelcircuit and provides output for power consuming tools by a seriescircuit.

3. An apparatus according to claim 1,

wherein the means for at times conductively conmeeting the positivepoles of said battery units to the positive pole of said source and forconductively connecting the negative poles of said battery units tothenegative pole of .said source comprises a charging electrical connectormatingly engageable at times with said battery pack electrical connectorand having its electrical terminals conductively connected to saidsource of power; and

wherein the means for at times conductively interconnecting the poles ofsaid battery units to select the output voltage to said outlet powerterminals comprises a program connector matingly engageable at times tosaid battery pack connector and having its terminals conductivelyinterconnected for suitably interconnecting the poles of said batteryunits to permit selection of the output voltage and consumption of powerby said power tool when said program connector is engaged in said 2batterypack connector.

.An electric power apparatus comprising: a portable battery packcomprising 7 l. a plurality of battery units mounted in said pack,

each battery unit having a positive and a negative pole;-

' 2. a battery pack electrical connector having a pair of contacts for"each battery unit and having each pole of each battery unit connected toa different one of said contacts; and

3. a pair of output power terminals for connection to a power consumingtool; one output terminal conductively connected to a positive pole ofone battery unit and the other output terminal conductively connected tothe negative pole of another battery unit; and

b. a cooperating battery charging apparatus comprisc.- a programconnector matingly engageable at times to said battery pack connectorand having its terminals conductively interconnected for suitablyinterconnecting the poles of said battery units to permit selection ofthe output voltage and consumption of power by said power tool when saidprogram connector is engaged in said battery pack connector.

7 5. An apparatus according to claim 4,

wherein said battery units are parallel connected to said source ofcharging power by said charging connector when the charging connector isengaged in the battery pack connector and wherein the battery units areseries connected to said output terminals by said program connector whenthe program connector is engaged in the battery pack connector.

6. An apparatus according to claim 5,

wherein said battery pack has four, 6 volt battery units and whereinthere are two alternative program connectors matingly engageable to saidbattery pack connector, a first alternative program connector forconnecting all the battery units in parallel to said output terminalsand the second alternative program connector for connecting the batteryunits in two series connected pairs and for connecting these pairs inparallel to each other.

7. An apparatus according to claim 4,

wherein a control panel connector, matingly engageable to said programconnector, has a pair of first terminals serially interposed between apole of said source of charging power and said charging connector, saidfirst terminals opening the circuit when not interconnected and saidterminals being connected together to close said charging circuit bysaid program connector when said program connector is engaged to saidcontrol panel connector.

8. An apparatus according toclaim 7,

wherein a series connected ammeter and diode, connected in a polarity topermit charging current flow, are serially interposed between saidsource of charging power and said charging connector.

9. An apparatus according to claim 7,

wherein said control panel connector has a pair of second terminalsserially connected between said source of power and an indicator lampand wherein said second terminals are connected together by said programconnector when said program connector is engaged in said panel connectorand said lamp is illuminated to indicate engagement of the programconnector to the panel connector.

10. An apparatus according to claim 7,

wherein said battery units are parallel connected to said source ofcharging power by said charger connector when the charger connector isengaged in the battery pack connector and wherein the battery units areseries connected to said output terminals by said program connector whenthe program connector is engaged in the battery pack connector.

11. An apparatus according to claim 10,

wherein said apparatus includes a second battery pack similar to saidfirst battery pack, a second cooperating charging connector similar tosaid first charging connector, a second program connector similar tosaid first program connector, and a second control panel connectorsimilar to said first panel connector, to permit alternate charging ofone battery pack during consumption of power from the other battery packwherein a substantially continuous supply of power is available.

12. An apparatus according to claim 10,

wherein a control panel connector, matingly engageable to said programconnector, has a pair of first tenninals serially interposed between apole of said source of charging power and said charging connector, saidfirst terminals opening the charging circuit when not interconnected andsaid terminals being connected together to close said charging circuitby said program connector when said program connector is engaged to saidcontrol panel connector, wherein a series connected ammeter and diode,connected in a polarity to permit charging current flow, are seriallyinterposed between i said source of charging connector. .13. Anapparatus according to claim 1', wherein secondary outlet powerterminals are mounted to said charging apparatus, the means for at timesconductively connecting the positive poles of said battery units to thepositive'pole of said source and for conductively connecting thenegative poles of said battery units to the negative pole of said sourceand the means for at times conductively interconnecting the poles ofsaid battery units to select the output voltage to said outlet powerterminals comprises a double throw gang switch having a plurality ofmovable blades and having a plurality of fixed contacts for each of saidmovable blades. 14. A portable electric power apparatus comprising a. abattery pack comprising a box-like housing for containing battery unitsand having a rearwardly facing battery pack connector mounted to a rearwall of said housing, said connector being electrically connected tosaid battery units, said battery pack also having power outlet terminalsfor connection to a tool; and

b. a charger rack apparatus mountable to a motor vehicle, said rackcomprising:

1. a substantially vertically oriented rear panel;

2. a first support cradle comprising a track extending substantiallyhorizontally from said rear panel for slidably receiving said batterypack;

3. a forwardly facing charging connector mounted to said rear panel andpositioned to slidingly engage said battery pack connector as saidbattery pack is slid into said first cradle toward said rear panel, saidcharging connector being electrically connected to battery chargingcircuitry whichis connected to said charger rack.

15. An apparatus according to claim 14,

wherein said track comprises four, parallel, right angle structuralbeams for slidably receiving in their acute angles four side edges ofsaid housing and for retaining said housing against vertical and lateralmovement.

16. An apparatus according to claim 14,

wherein a second similar battery pack is provided;

wherein the charger rack further comprises a second support cradlevertically above said first support cradle and comprising a second trackextending substantially horizontally from said rear panel for slidablyreceiving said second battery pack; and

wherein a second, forwardly facing charging connector is mounted to saidrear panel and positioned to slidably engage a second battery packconnector of said second battery pack as said second battery pack isslid along said second track toward said rear panel, said secondcharging connector also being connected to said battery chargingcircuitry.

17. An apparatus according to claim 16,

wherein each of said tracks comprises four, parallel,

ri t ri ht a e structural beams f r slidabl re c eivin g in tii ir acuteangles, four si e edges 0 said housing and for retaining said housingagainst vertical and lateral movement; 18. An apparatus according toclaim 16, wherein said charging circuitry has a control panel which ismounted intermediate said tracks.

1. An electric power apparatus comprising: a. a portable battery packcomprising:
 1. a plurality of battery units mounted in said pack, eachbattery unit having a positive and a negative pole;
 2. a battery packelectrical connector having a pair of contacts for each battery unit andhaving each pole of each battery unit connected to a different one ofsaid contacts;
 3. a pair of output power terminals for connection to apower consuming tool; and
 4. means for conductively connecting oneoutput terminal to a positive pole of one battery unit and the otheroutput terminal to the negative pole of another battery unit; and b. acooperating battery charging apparatus comprising:
 1. a source of inputd-c charging power having a positive pole and a negative pole;
 2. meansfor at times conductively connecting the positive poles of said batteryunits to the positive pole of said source and for conductivelyconnecting the negative poles of said battery units to the negative poleof said source; whereby when said source is so connected the batteryunits are connected to said source in parallel and the batteries arecharged in parallel; and c. means for at times conductivelyinterconnecting the poles of said battery units to select the outputvoltage to said output power terminals to provide for selectedconsumption of power by said power tool.
 2. a battery pack electricalconnector having a pair of contacts for each battery unit and havingeach pole of each battery unit connected to a different one of saidcontacts;
 2. means for at times conductively connecting the positivepoles of said battery units to the positive pole of said source and forconductively connecting the negative poles of said battery units to thenegative pole of said source; whereby when said source is so connectedthe battery units are connected to said source in parallel and thebatteries are charged in parallel; and c. means for at timesconductively interconnecting the poles of said battery units to selectthe output voltage to said output power terminals to provide forselected consumption of power by said power tool.
 2. An apparatusaccording to claim 1, wherein the means for at times conductivelyinterconnecting the poles of the battery units at times interconnect thepoles of at least two of the battery units in series to at least doublethe output voltage of said battery pack above the output voltage of anyindividual battery unit; whereby the portable electric power apparatusis charged in a parallel circuit and provides output for power consumingtools by a series circuit.
 2. a charging electrical connector matinglyengageable at times with said battery pack connector and having itselectrical terminals conductively connected to said source of power forconductively connecting the positive poles of said battery units to thepositive pole of said source and for conductively connecting thenegative poles of said battery units to the negative pole of said sourcewhenever said charging connector is conductively engaged to said batterypack connector; and c. a program connector matingly engageable at timesto said battery pack connector and having its terminals conductivelyinterconnected for suitably interconnecting the poles of said batteryunits to permit selection of the output voltage and consumption of powerby said power tool when said program connector is engaged in saidbattery pack connector.
 2. a first support cradle comprising a trackextending substantially horizontally from said rear panel for slidablyreceiving said battery pack;
 2. a battery pack electrical connectorhaving a pair of contacts for each battery unit and having each pole ofeach battery unit connected to a different one of said contacts; and 3.a pair of output power terminals for connection to a power consumingtool; one output terminal conductively connected to a positive pole ofone battery unit and the other output terminal conductively connected tothe negative pole of another battery unit; and b. a cooperating batterycharging apparatus comprising
 3. a forwardly facing charging connectormounted to said rear panel and positioned to slidingly engage saidbattery pack connector as said battery pack is slid into said firstcradle toward said rear panel, said charging connector beingelectrically connected to battery charging circuitry which is connectedto said charger rack.
 3. An apparatus according to claim 1, wherein themeans for at times conductively connecting the positive poles of saidbattery units to the positive pole of said source and for conductivelyconnecting the negative poles of said battery units to the negative poleof said source comprises a charging electrical connector matinglyengageable at times with said battery pack electrical connector andhaving its electrical terminals conductively connected to said source ofpower; and wherein the means for at times conductively interconnectingthe poles of said battery units to select the output voltage to saidoutlet power terminals comprises a program connEctor matingly engageableat times to said battery pack connector and having its terminalsconductively interconnected for suitably interconnecting the poles ofsaid battery units to permit selection of the output voltage andconsumption of power by said power tool when said program connector isengaged in said battery pack connector.
 3. a pair of output powerterminals for connection to a power consuming tool; and
 4. means forconductively connecting one output terminal to a positive pole of onebattery unit and the other output terminal to the negative pole ofanother battery unit; and b. a cooperating battery charging apparatuscomprising:
 4. An electric power apparatus comprising: a. a portablebattery pack comprising
 5. An apparatus according to claim 4, whereinsaid battery units are parallel connected to said source of chargingpower by said charging connector when the charging connector is engagedin the battery pack connector and wherein the battery units are seriesconnected to said output terminals by said program connector when theprogram connector is engaged in the battery pack connector.
 6. Anapparatus according to claim 5, wherein said battery pack has four, 6volt battery units and wherein there are two alternative programconnectors matingly engageable to said battery pack connector, a firstalternative program connector for connecting all the battery units inparallel to said output terminals and the second alternative programconnector for connecting the battery units in two series connected pairsand for connecting these pairs in parallel to each other.
 7. Anapparatus according to claim 4, wherein a control panel connector,matingly engageable to said program connector, has a pair of firstterminals serially interposed between a pole of said source of chargingpower and said charging connector, said first terminals opening thecircuit when not interconnected and said terminals being connectedtogether to close said charging circuit by said program connector whensaid program connector is engaged to said control panel connector.
 8. Anapparatus according to claim 7, wherein a series connected ammeter anddiode, connected in a polarity to permit charging current flow, areserially interposed between said source of charging power and saidcharging connector.
 9. An apparatus according to claim 7, wherein saidcontrol panel connector has a pair of second terminals seriallyconnected between said source of power and an indicator lamp and whereinsaid second terminals are connected together by said program connectorwhen said program connector is engaged in said panel connector and saidlamp is illuminated to indicate engagement of the program coNnector tothe panel connector.
 10. An apparatus according to claim 7, wherein saidbattery units are parallel connected to said source of charging power bysaid charger connector when the charger connector is engaged in thebattery pack connector and wherein the battery units are seriesconnected to said output terminals by said program connector when theprogram connector is engaged in the battery pack connector.
 11. Anapparatus according to claim 10, wherein said apparatus includes asecond battery pack similar to said first battery pack, a secondcooperating charging connector similar to said first charging connector,a second program connector similar to said first program connector, anda second control panel connector similar to said first panel connector,to permit alternate charging of one battery pack during consumption ofpower from the other battery pack wherein a substantially continuoussupply of power is available.
 12. An apparatus according to claim 10,wherein a control panel connector, matingly engageable to said programconnector, has a pair of first terminals serially interposed between apole of said source of charging power and said charging connector, saidfirst terminals opening the charging circuit when not interconnected andsaid terminals being connected together to close said charging circuitby said program connector when said program connector is engaged to saidcontrol panel connector, wherein a series connected ammeter and diode,connected in a polarity to permit charging current flow, are seriallyinterposed between said source of charging connector.
 13. An apparatusaccording to claim 1, wherein secondary outlet power terminals aremounted to said charging apparatus, the means for at times conductivelyconnecting the positive poles of said battery units to the positive poleof said source and for conductively connecting the negative poles ofsaid battery units to the negative pole of said source and the means forat times conductively interconnecting the poles of said battery units toselect the output voltage to said outlet power terminals comprises adouble throw gang switch having a plurality of movable blades and havinga plurality of fixed contacts for each of said movable blades.
 14. Aportable electric power apparatus comprising a. a battery packcomprising a box-like housing for containing battery units and having arearwardly facing battery pack connector mounted to a rear wall of saidhousing, said connector being electrically connected to said batteryunits, said battery pack also having power outlet terminals forconnection to a tool; and b. a charger rack apparatus mountable to amotor vehicle, said rack comprising:
 15. An apparatus according to claim14, wherein said track comprises four, parallel, right angle structuralbeams for slidably receiving in their acute angles four side edges ofsaid housing and for retaining said housing against vertical and lateralmovement.
 16. An apparatus according to claim 14, wherein a secondsimilar battery pack is provided; wherein the charger rack furthercomprises a second support cradle vertically above said first supportcradle and comprising a second track extending substantiallyhorizontally from said rear panel for slidably receiving said secondbattery pack; and wherein a second, forwardly facing charging connectoris mounted to said rear panel and positioned to sLidably engage a secondbattery pack connector of said second battery pack as said secondbattery pack is slid along said second track toward said rear panel,said second charging connector also being connected to said batterycharging circuitry.
 17. An apparatus according to claim 16, wherein eachof said tracks comprises four, parallel, right right angle structuralbeams for slidably receiving in their acute angles, four side edges ofsaid housing and for retaining said housing against vertical and lateralmovement.
 18. An apparatus according to claim 16, wherein said chargingcircuitry has a control panel which is mounted intermediate said tracks.